In a touch panel display device which has recently been spread at a high rate, a transparent electrode including a transparent conductive layer made of an indium-tin composite oxide (ITO) or the like has been used. Although a conductive body with a transparent electrode used for a touch panel fundamentally uses a glass or plastic film as a substrate, a transparent conductive film using a plastic film is preferably used in a smart phone or tablet particularly requiring portability from the viewpoint of thinness and weight.
In recent years, improvements in the sensor sensitivity or resolution of the transparent electrode have been demanded against the background of the high grade of the touch panel. As a result, the level of the specific resistance value required for the transparent conductive layer tends to be increasingly decreased.
In the meantime, since the transparent conductive layer is brittle, the transparent conductive layer is easily deteriorated under the influence of external factors, which is apt to cause an increase in a specific resistance value. Therefore, in order to keep the specific resistance value of the transparent conductive film low, it is necessary to improve the maintenance reliability of the specific resistance value of the transparent conductive film so as to numerically decrease the specific resistance value of the transparent conductive layer and to allow the value to be maintained as much as possible.
Examples of the external factors causing the deterioration include physical contact such as collision or friction to the surface of the transparent conductive layer. The physical contact easily causes flaws on the surface of the transparent conductive layer, which is apt to cause an increase in the resistance value of the surface.
Particularly, when the transparent conductive film is handled in various processing treatments required in order to use the transparent conductive film as a touch panel sensor (for example, pattern etching treatment), flaws may be caused on the surface of the transparent conductive layer of the transparent conductive film, which disadvantageously has a bad influence on resistance characteristics.
Hitherto, in order to address scratch resistance, the present inventors have proposed to obtain a transparent conductive laminate improved in transparency, scratch resistance, and bending resistance or the like by forming a transparent dielectric thin film such as an SiO2 thin film, on one side of a transparent film substrate, and a transparent conductive thin film made of an indium-tin composite oxide or the like, on the SiO2 thin film, or laminating a transparent substrate on the opposite side of the film substrate via an adhesive layer (see Patent Document 1).